Reduced toxicity of intravitreally injected liposome-encapsulated cytarabine.

Cytarabine has been demonstrated to be a more potent inhibitor of fibroblast proliferation than fluorouracil. It is, however, more toxic to the retina. We evaluated the ocular toxicity of liposome-encapsulated cytarabine in vitrectomized and nonvitrectomized rabbit eyes by ophthalmic and histopathologic examination. In the vitrectomized group, doses of up to 26 micrograms were nontoxic to the retina. In nonvitrectomized eyes, doses of up to 55 micrograms were nontoxic. Doses of 85 micrograms resulted in loss of ganglion cells and disorganization of photoreceptor cells. The results obtained in this study demonstrated a substantial reduction in ocular toxicity of liposome-encapsulated cytarabine, as compared with a previous study which employed free drug. By virtue of its reduced toxicity, cytarabine in a liposomal vehicle may be of value in the treatment of ocular proliferative disorders.